Sixty-five brands of cigarettes now marketed in New York City will be characterized in terms of their inorganic constituents. Inorganic components of plants occur naturally, sometimes in a form referred to as opal phytoliths. These inorganic components are now augmented with materials added during production of tobacco sheet, e.g., diatomaceous earth, clays, fibrous glass, ceramic fiber and asbestos. Macerated tobacco sheet is included in some cigarettes as filler. We propose to determine the relative proportion of natural and added inorganics in cigarettes. We will determine the nature of the inorganic phases, their identity, relative proportions and size distributions. For each cigarette we will gravimetrically determine the average unit weight, the weight of total filler, the weight of tobacco in the filler, the weight of tobacco sheet. Both of the fillers (natural tobacco and tobacco sheet) will be ashed at low temperatures (nascent oxygen) and at 500 degrees centigrade to determine their ash residues. Each ash residue will be examined by polarized light microscopy, x-ray diffraction, electron microscopy, electron diffraction, and the electron microprobe. Once the nature of the inorganic components is determined, the main-stream and side-stream smokes from these cigarettes will be collected on membrane filters by means of personal samplers. The particles which become airborn, and those which penetrate cigarette filters, will be characterized by all the techniques outlined for the ashed residues.